Stencil washing apparatus



. Aug. 29, 1944. R, v, MCKINLEY 2,356,771

STENCIL WASHING APPARATUS Filed Jan. 5, 1942 F1/3.2. il! l ,22

@as 3 wuz/who@ 2:5 74 REX V. MOK/NLEY /btqwlma Patented Aug. 29, 1944 UNITED STATES ATENT OFFHCE (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 O. G. 757) 3 Claims.

The invention described herein may 'be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to improvements in apparatus for removing ink or other foreign substances and otherwise cleaning stencils of the kind commonly used in reproducing machines of the general class shown and described in United States Letters Patent No. 2,162,346, granted June 13, 1939, to Sherlie E. Gregory.

It is well known that after a number of impressions have been made the stencil becomes somewhat clogged with dried ink and accumulations of dust. In order to increase the number of suitable impressions that can be secured from any particular stencil it is necessary to resort to Some method of cleaning the stencil.

It is also customary in many oliices to keep a le of the stencils which have been used in order that extra impressions may be made should the occasion arise. In order to maintain such a file it is necessary that the stencils be thoroughly cleaned and freed from ink before ling.

Various methods of cleaning have been used in the past, none of which has proved completely satisfactory. The stencils have been dried between pieces of blotting paper, washed in a tray of ink-dissolving uid, or washed in an ordinary sink under running water. All oi these methods are time-consuming and the manipulations required make it practically impossible to avoid splattering of the ink and, consequently, to maintain the appearance of the ofiice.

It is, accordingly, the -ob-,iect of my invention to provide an arrangement for washing and cleaning stencils which will overcome the objections inherent in prior systems; to provide a stencil cleaner which will be simple to construct and operate and which will provide the maximum of cleaning in the minimum of time.

For the purposes of illustration I have described and illustrated my invention in conjunction with a, machine designed to be operated to clean stencils which have been used with water-soluble ink. It is obvious, however, that by means of a suitable circulating system and ink solvent, the advantages of my invention are equally applicable to any type of stencil. I therefore wish it to be understood that I do not wish to be limited to the particular details and arrangements shown.

Other objects and advantages of my invention will be apparent from a consideration of the following description taken in conjunction with the accompanying drawing in which:

Fig. 1 is a plan view of my improved machine in which, for purposes of clarity, the cover has not been shown;

Figl 2` is a longitudinal view'of the machine taken along the line 2-2 of Fig. 1;

Fig. 3 is a longitudinal view of the machine taken along the line 3 3 of Fig. l;

Fig. 4 is an enlarged view showing the construction of the guide members and the channels formed thereby;

Fig. 5 is an enlarged view showing the relative dimensions of the spray pipes and the angularity of the spray holes;

Fig. 6 is a front View of the stencil holder; and

Fig. '7 is a longitudinal view along the line 'I-'I of Fig. 6.

Referring to Figs. 1, 2, and 3, it will be seen that my improved machine consists of a tank and fluid circulating means. The tank, which is prefs erably constructedv of sheet metal, consists of a bottom I and sides 2, joined togetherso as to be water-tight. The sides 2 of the tank are made of suflicient depth so that the stencil may be entirely inclosed therein. The bottom I is provided with a central opening 3 to provide an outlet for the cleaning fluid. The used fluid is drained off through opening 3 by means of drain pipe 4, attached to the bottom by means of base plate 5. Horizontally aligned spray pipes 6 and 'I extend across the tank and are placed a little below the top of the tank. The spray pipes 6 and l are connected to the feed pipe 8 by means of suitable couplings 9 and I0 respectively. The free ends of the spray pipes 6 and 'I are closed by means of caps II and I2, respectively. The feed pipe 8 is connected to the supply pipe I3 through control valve I4. The spray pipes '6 and I may be supported in the sides by grommets I5, or any other suitable packing, although, as will be explained later, the position of the spray holes I6 in these pipes will make this unnecessary. Along the sides 2 and centrally located between the spray pipes 6 and 'I are placed guides I'I. The guides I1 consist of extended members attached to the sides and form a channel adapted toreceive the stencil holder. The cover I8 is formed to make a snug nt with the top of the tank and is provided with hinges I9 and handle 20. If desired the cover I8 may be provided with overlapping sides 2|.

In Fig. 4 I have illustrated a preferred construction of the channel-forming guides II. It will be seen that each guide consists of a single piece of sheet metal folded back on itself and having the ends of the sides folded at right angles forming a T member which is readily attachable to the sides 2.

Referring to Fig. 5, it will be clear that the spray holes I6 have been placed at an angle, preferably 30, and that the spray pipe 6 is of smaller diameter than that of the spray pipe l to eiect a difference in capacity and a corresponding difference in pressure at the spray holes or openings I6. By placing the spray holes I6 at an angle there results a minimum of splash and, therefore, the maximum amount of cleaning fluid comes into contact with the stencil to be cleaned. Since the greatest portion of the ink appears on one side of the stencil, cleaning from the spray pipe of greater capacity is directed against this side, and a large saving in cleaning fluid is thus realized by using a smaller diameter spray pipe for the other side.

In Figs. 6 and 7 I have illustrated a preferred embodiment of a frame for supporting the stencil Within the tank. It consists of two side members 22 of a length substantially that of the depth of the tank below the spray pipes 6 and 'l and width substantially Athat of the channel formed by the guides I1; and two end members 23 of sufficient length to give the completed frame a width substantially that of the inside width of the tank. Across the top end member are placed studs 24 of sufficient number and located so as to engage the corresponding holes in the stencil. The face of the frame is covered With a wire screen 25, preferably of copper o-r bronze, and acts to support and position the stencil.

In operation, the stencil to be cleaned is placed on the studs 24 with the uninked surface placed against the screen 25. The frame is then placed in the channels formed by the guides il with the inked surface facing the larger spray pipe 1. 'I'he cover is then closed and the valve i4 opened admitting the cleaning fluid to the spray pipes 6 and 1. The cleaning fluid is ejected from the spray holes I6 and flows over the stencil on both sides, cleaning it. The cleaning fluid then drains off and leaves the tank by means of opening 3 and drain pipe d.

While, for simplicity in explanation and ease in understanding my invention, I have limited my drawing and discussion to the mere essentials, various modifications will suggest themselves to one skilled in the art. The cleaning machine can be constructed on legs or set on a table; it may be constructed in multiple so that more than one stencil can be washed; commercial types of spray nozzles may be used in place of perforations in the spray pipe; or driers may be used in association with the machines. So long as these modifications fall within the spirit of the claims, it is my desire to include them as my invention.

Having described my invention, what I claim as new and wish to secure by Letters Patent is:

1. A stencil cleaning apparatus comprising a tank, vertically disposed channel guides attached to the inner surfaces of opposite sides of said tank, a stencil holder adapted to be slidably itted within said channel guides, said stencil holder comprising a rectangular frame, a wire screen attached to said frame and studs projecting from the upper portion of said frame adapted to support a stencil adjacent said screen, spray pipes of larger and smaller diameter bridging said opposite sides of said tank adjacent the upper ends of said channel guides, said spray pipes being provided With spray holes adapted to direct streams of cleaning fluid diagonally downwardly against the opposite surfaces of the stencil at greater and lesser rates of flow corresponding respectively with their diameters, so as to impinge said surfaces with a minimum of splash, and a drain pipe connected to the bottom of said tank to drain off the cleaning fluid.

2. A stencil cleaning apparatus comprising a rectangular tank provided with a hingedly connected cover, vertically disposed parallel T- shaped members attached centrally to the inner surfaces of opposite sides of said tank to form channel guides, a stencil holder adapted to be slidably tted within said channel guides, said stencil holder comprising a rectangular frame formed With upper, lower, and lateral members, a wire screen attached to said members and studs projecting from said upper member adapted to support a stencil adjacent said screen, spray pipes of larger and smaller diameter bridging said opposite sides of said tank adjacent the upper ends of said channel guides, said spray pipes being provided with spray holes adapted to direct streams of cleaning fluid downwardly at angles of 30 to the horizontal so as to impinge the opposite surfaces of the stencil at greater and lesser rates of flow corresponding respectively with their larger and smaller diameters with a minimum splash, and a drain pipe connected to the bottom of said tank to drain off the cleaning fluid.

3. A stencil cleaning apparatus comprising a tank having rectangularly disposed side walls and bottom plate, and a hingedly connected cover, vertically disposed parallel T-shaped members attached centrally to the inner surfaces of op; posite sides of said tank to form channel guides, a stencil holder adapted to be slidably fitted within said channel guides, said stencil holder comprising a rectangular frame formed with upper, lower, and lateral members, a wire screen attached to said members and studs projecting from said upper member adapted to support a stencil with its less heavily inked surface adjacent said screen, means for spraying said stencil, said means comprising a valve-controlled feed pipe connected to spray pipes of larger and smaller diameter bridging said opposite sides of said tank adjacent the upper ends of said channel guides; said spray pipes being provided with spray holes adapted to direct streams of cleaning iiuid'l of. greater and lesser rates of flow correspondingA respectively with their diameters and downwardly at angles of 30 to the horizontal so as to impinge respectively the more and the less heavily inked opposite surfaces of the stencil with a minimum splash, and a drain Vpipe connected to the bottom of said tank to drain off the cleaning fluid.

REX V. MCKINLEY. 

